This invention is related to the Liquid Projecting Device disclosed in U.S. Pat. No. 4,735,239, by Michael E. Salmon and John S. Briski, which is incorporated by reference. The referenced device employs a tubular elastic bladder for receiving a liquid, a nozzle affixed to the bladder for projecting a stream of liquid, and a control valve for regulating the discharge.
The referenced device is perfectly adequate for its intended purpose of projecting a liquid and represents significant advances over prior art, but it was not designed for the purpose of storing and dispensing fluids at substantially constant pressures and of storing fluids in a substantially chemically inert and impermeable environment for long periods.
Other fluid storing and dispensing devices using elastic bladders have been known for some time. Refer, for example, to the flowable substances dispenser disclosed by U.S. Pat. No. 3,672,543 to Roper et al. This dispenser includes an expandable bladder and a unitary mandrel and valve closure member supported by a container. The bladder is made of an elastomeric material, such as natural latex or silicone rubber, and appears to be formed by a dipping process rather than by extrusion. It has an opening at one end and extends therefrom in portions having various inside diameters. The mandrel fits inside the bladder, maintaining it in a longitudinally stretched condition which serves to provide force to dispell fluids disposed therewithin when the valve is opened.
U.S. Pat. No. 3,738,538 to Roper et al. also discloses a dispenser for flowable substances. This dispenser includes a similar bladder, but it is held in a longitudinally stretched condition by disposing a spherical member inside its closed end and retaining the member with a snap fitting mounted on the container. The bladder is twisted to force out through the valve all fluid contained within the bladder.
U.S. Pat. No. 3,791,557 to Venus discloses a nonaerosol container having an expandable bladder and a sheath for providing expelling force. The device includes an expandable bladder, a mandrel, a sheath and a valve closure member supported by a container. The bladder is made of an elastomeric material, such as natural latex or silicone rubber that is chemically compatible with whatever fluid is to be stored within it, and appears to be formed by a dipping process rather than by extrusion. It has an opening at one end and extends therefrom, having an ever decreasing inside diameter, to a closed end. The mandrel fits inside the bladder without expanding it. The bladder, in turn, fits within a sheath. The sheath is a tube, open at each end, made of latex or natural rubber having a high modulus of elasticity, the sheath furnishing most of the fluid expelling force.
A double expansible bladder container is disclosed by Venus in U.S. Pat. No. 3,876,115. The device includes a pair of bladders. A first bladder, made of a butyl-like elastomer, is designed to be chemically compatible with whatever fluid is to be stored within it. A second bladder, made of a latex-type compound, is designed to substantially surround the first and is the primary source of the fluid expelling force. The mandrel used in this device is only slightly longer than the first bladder.
A liquid dispensing and metering assembly is disclosed in U.S. Pat. No. 3,486,539 by Jacuzzi. The disclosed assembly includes an expansible receptacle of a material adapted to maintain constant pressure characteristics over a substantial change in volume of liquid content of the receptacle. The assembly discharges through a slow-rate metering element to provide a uniform discharge flow at a low, constant pressure.
U.S. Pat. No. 4,419,096 to Leeper et al. discloses an elastomeric bladder assembly designed to operate at a constant pressure to maintain a constant dispensing rate. The assembly includes a bladder having within its lumen a bolus forming means that prevents the bladder from collapsing to a cylindrical configuration, thereby inhibiting a sharp rise in pressure just prior to the end of a duty cycle.
U.S. Pat. No. 4,432,829 to Katz discloses an apparatus for containing and dispensing fluids under pressure. The apparatus includes a flexible, chemically inert container having longitudinally extending creases to provide for radially inward folding of the container when being emptied and radially outward expansion when being filled. An open-ended, radially elastic, tubular, fabric sleeve surrounds the container when folded. An open-ended, tubular, resilient member is disposed about the fabric sleeve when the container is folded. The resilient member is controlled by frictional interaction with the fabric sleeve, which enables the resilient member to expand in substantially radial directions when the container is filled with a fluid under pressure.
While each of these devices functions with a certain degree of efficiency, none disclose the means of the present invention for providing the advantage of substantially eliminating the rises in pressure that occur proximate the bladder fill times as well as those that occur proximate the discharge times; and none disclose the means of the present invention for providing the advantage of considerably increasing the number of fill cycles prior to bladder failure.
Other fluid storing and dispensing devices using elastic bladders are disclosed by U.S. Pat. Nos. 1,392,861; 3,025,634; 3,940,026; 4,121,737; 4,134,228; 4,222,499; 4,257,460; 4,324,350; 4,387,833; 4,555,295; and 4,458,830.